applications of self-healing nanotechnology in urban infrastructure

Session A4
Disclaimer — This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University
of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is based on
publicly available information and may not be provide complete analyses of all relevant data. If this paper is used for any
purpose other than these authors’ partial fulfillment of a writing requirement for first year (freshman) engineering students at
the University of Pittsburgh Swanson School of Engineering, the user does so at his or her own risk.
Nowa Bronner, [email protected], Mahboobin 4:00, Jonah Cohen, [email protected], Mahboobin 4:00
Revised Proposal -- In the world of urban infrastructure,
concrete dominates all other construction materials in
popularity. The Romans’ use of concrete in the Pantheon and
Colosseum shows the beginning of its ubiquitous nature in
urban settings. The wide usage of concrete can be attributed
to its long life span, strength, and reliability. However, it
certainly does have some drawbacks. When water enters the
pores of the concrete, and expands when the temperature
drops below freezing, the resulting ice creates cracks in the
material. As this process continues every winter, the cracks
become larger and larger, causing major problems in the
concrete of structures all around the world. As time passes,
buildings start to degrade, and an enormous amount of money
must be spent to repair them. The Romans’ solution to the
forces of freezing and thawing included the mixing of blood
in the concrete, as the blood would produce tiny air voids in
the cement paste and thereby protect the concrete from these
violent forces. However, in this contemporary society, this
method would hardly be accepted. Instead, modern scientists
and engineers have been researching nanotechnology for
years, and they believe this technology may be the solution.
Nanotechnology is a field of science that deals with
particles with at least one dimension between 1 and 100nm.
To put this into perspective, a piece of paper is around
100,000nm thick. While nanotechnology is not brand-new, it
has been growing rapidly in the past decade. Through the use
of many recent developments in nanotechnology, a more
durable and even self-healing concrete has been created, and
may be used in the future of urban infrastructure.
In order for this concrete to have self-healing properties,
a network of carbon nanotubes (CNTs) must be embedded in
it. CNTs show superior electrical and mechanical properties,
and can be used to create concrete with excellent self-sensing
abilities. This means the concrete can detect strain, stress,
and cracking, which allows quick repairs to be made before
the damage is too great. When the CNTs detect damage,
healing agents, including nano-SiO2 (silica) and an epoxy
sealing compound are released into the affected area [1].
Because the primary component of strength in concrete,
calcium silicate hydrate (C-S-H) phase, lies within the
University of Pittsburgh, Swanson School of Engineering 1
nanometer-scale, nanotechnology has the possibility to
significantly increase the durability of concrete. This silica
improves the performance of concrete by filling in the nanosize pores of the cement paste, and through a chemical
reaction with Ca(OH)2, which creates more C-S-H [2]. Silica
is not the only nano-particle that has healing properties.
Research shows that Fe2O3, Al2O3, and ZrO2 also promote the
strength of concrete [3]. This paper will compare the
durability and longevity of untreated concrete with
nanotechnology-induced concrete, describe the chemical,
mechanical, and electrical processes involved in improving
concrete, and discuss the impact this technology could have
on the future of urban infrastructure.
[1] K. Sobolev, S. Shah. (2015). “Nanotechnology in
Construction.” Springer International Publishing Switzerland.
(Online Publication). DOI: 10.1007/978-3-319-17088-6_46.
p. 357
[2] B. Bjorn, A. Mukhopadhyay, G. Geary, M. Khan, K.
Sobolev. (2012). “Nanotechnology in Concrete Materials.”
Transportation Research Board. (Online Publication).
[3] R. Olar. (2011). “Nanomaterials and Nanotechnologies for
Civil Engineering.” Buletinul Institutului Politehnic Din Iasi.
(Online Article).
B. Bjorn, A. Mukhopadhyay, G. Geary, M. Khan, K. Sobolev.
(2012). “Nanotechnology in Concrete Materials.”
Transportation Research Board. (Online Publication). p.
This online publication from a respected, professional
research board provides research results on the improvements
Nowa Bronner
Jonah Cohen
nanoparticles have on concrete. The results show that SiO2
and Fe2O3 nanoparticles both have a positive effect on the
compressive and flexural strengths of cement. The
information provided also describe how these particles
improve concrete. We will use the research results in this
publication to clarify the science behind the nanoparticles’
potential in improving concrete.
This article from a distinguished engineering society
discusses the history of highway construction and the need for
innovation. It provides numbers on the mileage of roads and
the amount of traffic that travel on them on average. It then
discusses the attempts engineers have made in the past to
improve highway construction. We will demonstrate the
importance of self-healing concrete by using the facts
“The Concrete Conundrum.” (2008). Chemistry World.
p. 63
This online article from a chemistry journal reveals the
wide usage of concrete. It discusses the advantages and
disadvantages of concrete, and the reason behind it being the
most widely used material in the world. Concrete is a low
impact material, meaning that it has a relatively small carbon
footprint. We will use the information in this article to show
the importance of concrete in construction.
K. Sobolev, S. Shah. (2015). “Nanotechnology in
Construction.” Springer International Publishing Switzerland.
(Online Publication). DOI: 10.1007/978-3-319-17088-6_46.
p. 357
This online publication from a reputable publishing
company elucidates in detail the system of self-healing in
concrete. The article presents two nanoparticles that shows
promise in healing concrete: nanosilica and epoxy sealing
compound. In order for these two particles to be released into
the concrete, carbon nanotubes will be utilized. The electrical
and mechanical properties of carbon nanotubes will be
described by using the information from this.
D. Feldman. (2013). “Polymer Nanocomposites in Building,
Construction.” Journal of Macromolecular Science. (Online
Article). DOI: 10.1080/10601325.2014.871948
This online article from a reputable journal provides an
overview of the use of nanoparticles in concrete and asphalt.
This article discusses applications of carbon nanotubes and
TiO2 within concrete. Carbon nanotubes can not only
strengthen, but also monitor concrete. TiO2 is effective in
breaking down pollution on the concrete, allowing rainwater
to wash away unwanted dirt. This information provides us
with details on this type of nanotechnology use.
N. Musee, G. Foladori, D. Azoulay. (2012). “Social and
Development in Africa.” CSIR. (Online Article).
Because nanotechnology is a relatively new field, the
effects it has on the environment is still widely unknown. This
online article from a reputable research group presents an
ethical issue nanotechnology possesses. This article
specifically discusses the social and environmental impact
nanotechnology may have in Africa. We will use the
information presented to address and discuss the effects this
technology may have on any society.
F. Pacheco-Torgal, S. Jalali. (2011). “Nanotechnology:
Advantages and Drawbacks in the Field of Construction and
Building Materials.” Construction and Building Materials.
This online article from a respected journal discusses the
pros and cons of nanotechnology in building materials. The
article begins with an overview of how nanotechnology, such
as carbon nanotubes, can improve concrete. Later, it provides
information on the dangers of nanotechnology, specifically
considering the possibility of the toxicity of such materials.
This article will be used to analyze the ethical issues of
O. Ugwu, J. Arop, C. Nwoji. N. Osadebe. (2013).
“Nanotechnology as a Preventive Engineering Solution to
Highway Infrastructure Failures.” American Society of Civil
Engineers. (Online Article). DOI: 10.1061/ (ASCE)CO.19437862.0000670.
This online article from a recognized engineering society
focuses its attention to the use of nanotechnology in highways.
It displays results of several tests and represents them in
graphs to give a visual of how nanotechnology improves
highway infrastructure. It also provides a visual of the
chemical structure of SiO2, and describes its chemical
properties. The data will be useful in objectively showing the
effectiveness of SiO2.
K. Michel, J. Samuels, J. Sussman, P. Noble, R. Nuefville, R.
Skinner, T. Galambos. (2008). “The Bridge.” National
R. Olar. (2011). “Nanomaterials and Nanotechnologies for
Civil Engineering.” Buletinul Institutului Politehnic Din Iasi.
(Online Article).
Nowa Bronner
Jonah Cohen
This online article from a university gives us an overview
of many different types of nanoparticles that can be used in
concrete. It previews particles such as SiO2, carbon nanotubes,
silver, Al2O3, ZrO2, WO3, and ZnO. All of these nanoparticles
have unique characteristics that make each one useful in its
own way. We can compare these different nanoparticles and
show which characteristics are most valuable.
Suvo, L. Stonecypher. (2010). “Concrete Roads vs Asphalt
Roads.” Bright Hub Engineering. (Online Article).
This online article compares concrete roads to asphalt
roads by looking at the pros and cons of each. The main
disadvantage concrete has to asphalt is its price. The more
expensive paving cost of concrete, however, is justified by its
higher durability and smaller carbon footprint. Concrete is
becoming less and less popular for roads because of its cost,
but we will show that with nanotechnology, concrete may
outshine asphalt once again.
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